For smooth top, you need to sand it more, and more, with more and more bigger grit wetsanding paper untill you hit the smoothness you want. Mind you, holes will show up, but fill in those, sand more, and you will get there.

'Use the sense, it is a force attribute. Common as it is, among us all.'

I got home from work yesterday wanting to print some more of my blaster. sendt a job to my printer, and walked in to se if it started ok, only to find peises of plastic all over.
on closer inspecion it turns out the x belt pulley has failed spctacularly caled customer service where I bouht it, but they said I had tocal their service deparment, wich was only open from 10 to 3 bahhhhhhhh,

a quick check online tells me this is a comon problem, and a better part is awailable for 3d printing, but stil, failen after only a few hours is not comonplace.